I personally find automatic brightness adjustment very annoying. It's fine on mobile phones, but on a computer? That would just annoy me. Just being able to quickly adjust it with simple hotkeys is much better IMHO, and I think the software above allows this.
Also just a thought - but if your work environment has such a wide lighting difference depending on the hour of day, that may be a problem in itself. Too much direct sunlight isn't that good, and too little artifical lighting when there is little or no sunlight isn't good either. So I would try and fix this first, before toying with screen brightness. This is just me though.